Definition of nyah-nyah in English:

nyah-nyah

verb

(also nyah-nyah-nyah)
  • To behave in a childishly supercilious or derisive manner towards someone; to taunt someone.

Pronunciation

nyah-nyah

/ˌnjɑːˈnjɑː/ /ˈnjɑːˌnjɑː/ /ˌnjaˈnja/

Origin

1980s; earliest use found in Adweek (United States). Reduplication of nyah.